U.S. patent application number 15/933815 was filed with the patent office on 2018-09-27 for subcutaneous vascular assemblies for improving blood flow and related devices and methods.
The applicant listed for this patent is Merit Medical Systems, Inc.. Invention is credited to John William Hall, Craig Nordhausen.
Application Number | 20180271637 15/933815 |
Document ID | / |
Family ID | 63581380 |
Filed Date | 2018-09-27 |
United States Patent
Application |
20180271637 |
Kind Code |
A1 |
Hall; John William ; et
al. |
September 27, 2018 |
SUBCUTANEOUS VASCULAR ASSEMBLIES FOR IMPROVING BLOOD FLOW AND
RELATED DEVICES AND METHODS
Abstract
Medical devices and related method for improving blood flow to
regions of a patient are described herein. Some medical devices may
include a first graft portion, a second graft portion, and a
catheter portion disposed between the first graft portion and the
second graft portion. The medical device may be implanted into a
patient to establish a non-natural flow path.
Inventors: |
Hall; John William; (North
Salt Lake, UT) ; Nordhausen; Craig; (Palisade,
CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Merit Medical Systems, Inc. |
South Jordan |
UT |
US |
|
|
Family ID: |
63581380 |
Appl. No.: |
15/933815 |
Filed: |
March 23, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62476124 |
Mar 24, 2017 |
|
|
|
62476151 |
Mar 24, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/07 20130101; A61F
2/06 20130101; A61F 2/064 20130101; A61F 2002/068 20130101; A61L
27/56 20130101; A61F 2002/061 20130101 |
International
Class: |
A61F 2/06 20060101
A61F002/06; A61L 27/56 20060101 A61L027/56 |
Claims
1. A method for improving blood flow to a lower leg of a patient,
the method comprising: obtaining a medical device, the medical
device comprising: a first graft portion; a second graft portion;
and a catheter portion that differs in composition from the first
graft portion and the second graft portion, wherein the catheter
portion has a crush force that is greater than both a crush force
of the first graft portion and a crush force of the second graft
portion; and implanting the medical device into the patient such
that: the first graft portion is attached to vasculature at a first
location that is above a knee of the patient; the second graft
portion is attached to vasculature at a second location that is
below the knee of the patient; and the catheter portion is coupled
to and disposed between both the first graft portion and the second
graft portion; wherein the first graft portion, the second graft
portion, and the catheter portion, when implanted into the patient,
together form a lumen that extends from the first location that is
above the knee of the patient to the second location that is below
the knee of the patient.
2. The method of claim 1, wherein, when the medical device is
implanted into the patient, the first graft portion differs in
length from the second graft portion.
3. The method of claim 1, wherein implanting the medical device
into the patient comprises shortening one or both of the first
graft portion and the second graft portion prior to attachment of
one or both of the first graft portion and the second graft portion
to the vasculature.
4. The method of claim 1, wherein one or both of the first graft
portion and the second graft portion comprise an inner layer of
polymeric material, an outer layer of polymeric material, and a
porous tube disposed between the inner layer of polymeric material
and the outer layer or polymeric material, the porous tube
comprising a metal alloy.
5. The method of claim 4, wherein one or both of the first graft
portion and the second graft portion further comprise a silicone
layer disposed between the inner layer and the outer layer.
6. The method of claim 5, wherein one or both of the first graft
portion and the second graft portion comprise a medial portion and
a lateral portion, wherein the medial portion comprises the porous
tube and the lateral portion is devoid of the porous tube.
7. The method of claim 6, wherein the medial portion has a crush
force that is greater than a crush force of the lateral
portion.
8. The method of claim 4, wherein the outer layer comprises fibrous
PTFE.
9. The method of claim 1, wherein the medical device further
comprises beading disposed around a circumference of one or both of
the first graft portion and the second graft portion.
10. The method of claim 1, wherein: the medical device further
comprises a first connector and a second connector, and the first
connector attaches the catheter portion to the first graft portion
when the medical device is implanted into the patient; and the
second connector attaches the catheter portion to the second graft
portion when the medical device is implanted into the patient.
11. The method of claim 10, wherein the first graft portion and the
second graft portion are coupled to the catheter prior to
implantation of the medical device.
12. The method of claim 1, wherein the lumen is defined by a smooth
continuous surface, wherein the smooth continuous surface extends
across the first graft portion, the second graft portion, and the
catheter portion.
12. The method of claim 1, wherein at least a portion of the
medical device comprises a cell impermeable layer.
13. A medical device for improving blood flow to a lower leg of a
patient, the medical device comprising: a first graft portion; a
second graft portion; and a catheter portion that differs in
composition from the first graft portion and the second graft
portion, wherein the catheter portion has a crush force that is
greater than both a crush force of the first graft portion and a
crush force of the second graft portion; wherein the first graft
portion and the second graft portion are attached to the catheter
portion, thereby forming a lumen that extends through the first
graft portion, the catheter portion, and the second graft
portion.
14. The medical device of claim 13, wherein one or both of the
first graft portion and the second graft portion comprise an inner
layer of polymeric material, an outer layer of polymeric material,
and a porous tube disposed between the inner layer of polymeric
material and the outer layer of polymeric material, the porous tube
comprising a metal alloy.
15. The medical device of claim 14, wherein one or both of the
first graft portion and the second graft portion further comprise a
silicone layer disposed between the inner layer and the outer
layer.
16. The medical device of claim 13, wherein at least a portion of
the medical device comprises a cell impermeable layer.
17. The medical device of claim 14, wherein the inner layer
comprises porous PTFE.
18. The medical device of claim 13, wherein: the medical device
further comprises a first connector and a second connector, and the
first connector attaches the catheter portion to the first graft
portion; and the second connector attaches the catheter portion to
the second graft portion.
19. The medical device of claim 13, wherein the lumen is defined by
a smooth continuous surface, wherein the smooth continuous surface
extends across the first graft portion, the second graft portion,
and the catheter portion.
20. The medical device of claim 19, wherein the first connector and
the second connector are designed to create a continuous luminal
surface that resists thrombus formation.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 62/476,124, filed on Mar. 24, 2017 and titled,
"SUBCUTANEOUS VASCULAR ASSEMBLIES FOR IMPROVING BLOOD FLOW AND
RELATED DEVICES AND METHODS," and U.S. Provisional Application No.
62/476,151, filed on Mar. 24, 2017 and titled, "SUBCUTANEOUS
VASCULAR ASSEMBLIES FOR IMPROVING BLOOD FLOW AND RELATED DEVICES
AND METHODS," both of which are hereby incorporated by reference in
their entireties.
TECHNICAL FIELD
[0002] The present disclosure relates generally to the field of
medical devices. More particularly, some embodiments relate to
medical assemblies and devices for improving blood flow to regions
of a patient's body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The written disclosure herein describes illustrative
embodiments that are non-limiting and non-exhaustive. Reference is
made to certain of such illustrative embodiments that are depicted
in the figures, in which:
[0004] FIG. 1 is an exploded perspective view of a medical
device.
[0005] FIG. 2 is an assembled perspective view of the medical
device of FIG. 1.
[0006] FIG. 3 is a cross-sectional view of a graft of the medical
device of FIG. 1 through plane 3-3 of FIG. 1.
[0007] FIG. 4 is a cross-sectional view of a graft of the medical
device of FIG. 1 through plane 4-4 of FIG. 1.
[0008] FIG. 5 is a perspective view of a portion of the medical
device of FIG. 1.
[0009] FIG. 6 is a cross-sectional side view of a portion of the
medical device of FIG. 1.
[0010] FIG. 7 is a posterior view of a leg of a patient into which
the medical device of FIG. 1 has been implanted.
[0011] FIG. 8 is a perspective view of a portion of a medical
device according to another embodiment.
[0012] FIG. 9 is a perspective view of a medical device, according
to another embodiment.
[0013] FIG. 10 is a perspective view of a medical device, according
to another embodiment.
[0014] FIG. 11A is a cross-sectional side view of the medical
device of FIG. 10.
[0015] FIG. 11B is a cross-sectional side view of a medical device,
according to another embodiment.
[0016] FIG. 12 provides a side view of a portion of a medical
device according to another embodiment in which a collapsed collar
is disposed around a periphery of a graft portion.
[0017] FIG. 13 provides a side view of the portion of the medical
device of FIG. 12, with the collar in an uncollapsed
configuration.
[0018] FIG. 14 provides a cross-sectional side view of the portion
of the medical device of FIGS. 12 and 13 that is partially disposed
within the vasculature of a patient.
DETAILED DESCRIPTION
[0019] Many individuals suffer from insufficient blood flow to
regions (e.g., peripheral regions) of their body. For example, some
individuals suffering from peripheral artery disease experience
narrowing of one or more peripheral arteries (e.g., a superficial
femoral artery) to their leg(s) or arm(s). Such narrowing of the
arteries may reduce blood flow to one or more peripheral regions.
Insufficient blood flow to the extremities of the body can lead to
critical limb ischemia, gangrene, and/or amputation. Diabetes is
known to increase the risk of peripheral artery disease.
[0020] Insufficient blood flow to peripheral regions of a body may
result from other causes as well. For example, in addition to
atherosclerosis in peripheral arteries, blood flow to a peripheral
region may be impeded by some other blockage. In other cases, a
portion of an artery may be punctured or weakened, thereby
rendering the artery (or a portion of the artery) unsuitable for
providing long-term blood flow to a peripheral region.
[0021] Embodiments described herein may be used to form a
non-natural flow path that improves blood flow to regions of a
patient. For example, in some embodiments, a medical device that
includes a first graft portion, a second graft portion, and a
catheter portion that is coupled to and disposed between the first
graft portion and the second graft portion may be inserted into a
patient such that the first graft portion is attached to
vasculature at a first location that is above the knee of a patient
and the second graft portion is attached to vasculature at a second
location that is below the knee of the patient. The new flow path
that is established between the first location and the second
location may improve blood flow to a region (e.g., the lower leg or
feet) of the patient.
[0022] The components described herein may additionally or
alternatively be used to establish other non-natural flow paths
within a patient. In some embodiments, both ends of the non-natural
flow path are attached to vasculature of the patient. In other
embodiments, only one end of the non-natural flow path is attached
to vasculature of the patient. In some embodiments, the non-natural
flow path is disposed within the torso region of the patient. In
other embodiments, the non-natural flow path is disposed below the
waist. In some embodiments, the non-natural flow path extends from
above the waist to below the waist. In some embodiments, the
non-natural flow path traverses the knee (i.e., connects the upper
leg with the lower leg). In some embodiments, one end of the
non-natural flow path empties directly into a chamber of the heart.
Other suitable locations for non-natural flow paths formed by
medical devices described herein are possible and within the scope
of this disclosure.
[0023] The components of the embodiments as generally described and
illustrated in the figures herein can be arranged and designed in a
wide variety of different configurations. Thus, the following more
detailed description of various embodiments, as represented in the
figures, is not intended to limit the scope of the present
disclosure, but is merely representative of various embodiments.
While various aspects of the embodiments are presented in drawings,
the drawings are not necessarily drawn to scale unless specifically
indicated.
[0024] The phrase "coupled to" is broad enough to refer to any
suitable coupling or other form of interaction between two or more
entities. Thus, two components may be coupled to each other even
though they are not in direct contact with each other. For example,
two components may be coupled to one another through an
intermediate component. The phrase "attached to" refers to
interaction between two or more entities which are in direct
contact with each other and/or are separated from each other only
by a fastener of any suitable variety (e.g., an adhesive).
[0025] As used herein, the term "crush force" refers to the
magnitude of a two-dimensional force (e.g., pinch force) that is
applied perpendicular to the longitudinal axis of a tube that
causes deformation of the tube from an unconstrained state to a
constrained state in which the distance between opposite sides of
the tube is three quarters of the distance between opposite sides
of the tube when the tube is unconstrained. As used herein, the
term "hoop force" refers to the magnitude of a force that is
uniformly applied around a circumference of a tube to compress the
tube to three quarters of its initial diameter. A "medial" portion
of a graft is a portion of the graft that is oriented toward the
catheter portion of the medical device. The "lateral" portion of a
graft is a portion of the graft that is oriented away from the
catheter portion of the medical device. In other words, the medial
portion of a graft is positioned closer to the catheter portion
than is the lateral portion of the graft when the medical device is
in a fully assembled configuration. A "porous tube" is considered
to be porous even if the porous tubular structure is coated,
disposed between, or embedded within a non-porous polymer. For
example, a tubular wire structure that includes openings between
adjacent elements of wire is porous even if the tubular wire
structure is coated, disposed between, or embedded within a
non-porous polymer.
[0026] FIGS. 1-6 provide alternative views of a medical device 100
(or a portion thereof) for improving blood flow to a region of a
patient, such as a lower leg, a foot, an arm, or a hand. More
specifically, FIG. 1 provides an exploded perspective view of the
medical device 100. FIG. 2 provides an assembled perspective view
of the medical device 100. FIG. 3 provides a cross-sectional view
of the medical device 100 through plane 3-3 of FIG. 1. FIG. 4
provides a cross-sectional view of a portion of the medical device
100 through plane 4-4 of FIG. 1. FIG. 5 provides a close-up
perspective view of a portion of the medical device 100. And FIG. 6
provides a close-up cross-sectional view of the portion of the
medical device 100 shown in FIG. 4.
[0027] As shown in FIGS. 1-6, the medical device 100 includes first
graft portion 110, a second graft portion 120, and a catheter
portion 130. The first graft portion 110 may be attached to the
catheter portion 130 via a first connector 140, and the second
graft portion 120 may be attached to the catheter portion 130 via a
second connector 150. Stated differently, the catheter portion 130
may be coupled to and disposed between both the first graft portion
110 and the second graft portion 120. When coupled together, the
first graft portion 110, the second graft portion 120, and the
catheter portion 130 may together form a lumen 105 that extends
across an entirety of the medical device 100. Stated differently,
the lumen 105 may extend through the first graft portion 110, the
catheter portion 130, and the second graft portion 120.
[0028] In some embodiments, the first graft portion 110 and the
second graft portion 120 are of the same composition. In other
words, in some embodiments, the first graft portion 110 and the
second graft portion 120 are made from the same materials. In other
embodiments, the first graft portion 110 and the second graft
portion 120 differ in composition. In other words, in some
embodiments, the first graft portion 110 and the second graft
portion 120 may be made, at least in part, from different
materials. In some embodiments, the first graft portion 110 and/or
the second graft portion 120 are made from relatively flexible
materials. The first graft portion 110 and/or the second graft
portion 120 may be formed of material that is suitable for
anastomosis to a vein or artery of a patient.
[0029] In some embodiments, the first graft portion 110 and the
second graft portion 120 are the same length, while in other
embodiments, the first graft portion 110 and the second graft
portion 120 are of different lengths. In some embodiments, the
length of the first graft portion 110 and/or the second graft
portion 120 is determined by (1) the desired location for placement
in the patient and/or (2) the particular anatomy of the patient.
For example, the first graft portion 110 and the second graft
portion 120 may have lengths that facilitate the bypass of a
narrowed, obstructed, and/or damaged portion of an artery or
vein.
[0030] In some embodiments, the first graft portion 110 and/or the
second graft portion 120 comprise multiple layers, as shown in the
cross-sectional view of the first graft portion 110 provided in
FIG. 3.
[0031] For example, in the depicted embodiment, the first graft
portion 110 comprises an inner (i.e., luminal) layer 112. The inner
layer 112 may be formed from a polymer, such as porous PTFE. More
specifically, the inner layer 112 may be formed from expanded PTFE
or fibrous PTFE. In embodiments that use fibrous PTFE, the fibrous
PTFE may be formed by rotation of a spinneret (i.e., rotational
spun PTFE) and/or by subjecting a solution or dispersion comprising
PTFE to an electric field (i.e., electrospun PTFE). In some
embodiments, the inner layer 112 is configured to permit tissue
ingrowth. In some embodiments, the inner layer 112 provides an
antithrombic surface and/or an anti-inflammatory surface.
[0032] The first graft portion 110 may also include an outer (i.e.,
abluminal) layer 118. Like the inner layer 112, the outer layer 118
may be formed from a polymer, such as porous PTFE. More
specifically, the outer layer 118 may be formed from expanded PTFE
or fibrous PTFE. In embodiments that use fibrous PTFE, the fibrous
PTFE may be formed by rotation of a spinneret (i.e., rotational
spun PTFE) and/or by subjecting a solution or dispersion comprising
PTFE to an electric field (i.e., electrospun PTFE). In some
embodiments, the outer layer 118 is configured to permit tissue
ingrowth. In some embodiments, the outer layer 118 provides an
antithrombic surface and/or an anti-inflammatory surface.
[0033] In some embodiments, the outer layer 118 is identical in
composition to the inner layer 112. In other embodiments, the outer
layer 118 and the inner layer 112 differ in composition. In some
embodiments, the first graft portion 110 includes fibrous (e.g.,
rotational spun or electrospun) fluorinated ethylene propylene
(FEP).
[0034] In some embodiments, the first graft portion 110 includes an
intervening layer 116 that is disposed between the inner layer 112
and the outer layer 118. For example, in some embodiments, the
intervening layer 116 comprises one or more of silicone, FEP, and
polyether block amide (e.g., PEBAX). In some embodiments, the
intervening layer 116 is a silicone layer that allows for resealing
of the first graft portion 110 after puncture. In other words, in
some embodiments, at least a portion of the graft portion 110 may
be pierced by a needle or other sharp object. Once the needle or
other sharp object is retracted from the graft portion 110, the
intervening layer 116 may reseal about the aperture formed by the
inserted needle or sharp object, thereby preventing the leakage of
blood or other fluid across a wall of the first graft portion 110.
Such resealability may permit early cannulation of the first graft
portion 110 (e.g., cannulation within one week of
implantation).
[0035] In some embodiments, one or more layers of the first graft
portion 110 may comprise a cell impermeable layer, meaning a layer
that is impermeable to migration of at least certain body cells
across the layer. For example, the intervening layer 116 (including
embodiments wherein the intervening layer comprises silicone) may
comprise a cell impermeable layer. In other embodiments a cell
impermeable layer may be disposed as an outside layer, an inside
layer, or at any point between an outside and an inside layer.
Further, cell impermeable layers may be comprised of various
materials such as silicone, FEP, or other materials.
[0036] In some embodiments, as shown in FIG. 3, the first graft
portion 110 may include a porous tube 114 that is partially or
completely disposed between the inner layer 112 and the outer layer
118. Stated differently, the porous tube 114 may be disposed
between or embedded within one or more layers of polymer. In some
embodiments, the porous tube 114 is embedded within the intervening
layer 116. The porous tube 114 may strengthen or reinforce the
first graft portion 110. For example, in some embodiments, the
porous tube 114 is designed to increase the crush force of the
first graft portion 110.
[0037] In some embodiments, the porous tube 114 comprises and/or
consists of a metal alloy. For example, in some embodiments, the
porous tube 114 comprises and/or consists of a nickel-titanium
alloy, such as nitinol. In some embodiments, the porous tube is
formed by winding (e.g., helically wound nitinol) or braiding
(e.g., braided nitinol). In other embodiments, the porous tube is
formed by laser-cutting (e.g., laser-cut nitinol).
[0038] FIG. 4 provides a cross-sectional side view of the first
graft portion 110. As shown in FIG. 4, the porous tube 114--in some
embodiments--extends across only a portion of the length of the
first graft portion 110. For example, in some embodiments, the
porous tube 114 extends across only a medial portion 162 of the
first graft portion 110, but does not extend to a lateral portion
164 of the first graft portion 110. Stated differently, the first
graft portion 110 may include a medial portion 162 and a lateral
portion 164, wherein the medial portion 162 comprises the porous
tube 114 and the lateral portion 164 is devoid of the porous tube
114. The medial portion 162 of the first graft portion 110 may have
a crush force that is greater than a crush force for the lateral
portion 164. In other words, the porous tube 114 may provide
additional structural support for the medial portion 162, thereby
increasing the crush force of the medial portion 162 relative to
the lateral portion 164. The lateral portion 164 may be designed to
facilitate anastomosis to vasculature of a patient.
[0039] In some embodiments, the crush force and/or hoop force of
the porous tube 114 itself may vary across its length. For example,
in some embodiments, the porous tube 114 may have a lower crush
force and/or hoop force at a lateral end than at a medial end. More
specifically, in some embodiments in which the porous tube 114 is a
nickel-titanium (e.g., nitinol) braid, the density of the braiding
may be less within a lateral portion of the porous tube 114 than
within a medial portion of the porous tube 114, thereby causing the
lateral end of the porous tube 114 to have a lower crush force
and/or hoop force than a medial end of the porous tube 114.
[0040] In some embodiments, the first graft portion 110 lacks a
porous tube. In some instances, for example, the first graft
portion 110 may be a commercially known vascular graft, such as a
tri-layer vascular graft having an abluminal layer of expanded
PTFE, a luminal layer of expanded PTFE that has been coated with
heparin, and an intervening elastomeric layer. Other commercially
available grafts may alternatively be used. For example, in some
embodiments, the first graft portion 110 may be selected by the
practitioner based on its flexibility, tensile strength,
stretchiness, size, and/or resistance to kinking, and/or the
practitioner's experience with the graft portion 110.
[0041] The disclosure set forth above in connection with the first
graft portion 110 may apply to the second graft portion 120. Stated
differently, the second graft portion 120 may have any of the
features discussed above in connection with the first graft portion
110.
[0042] In some embodiments, the length(s) of the first graft
portion 110 and/or the second graft portion 120 are altered prior
to implantation of the medical device 100 into a patient. In some
embodiments, the length of the first graft portion 110 and/or the
second graft portion 120, when implanted within the patient, is
between 2 cm and 40 cm, such as between 2 cm and 10 cm, between 5
cm and 15 cm, between 10 cm and 20 cm, between 15 cm and 25 cm,
between 20 cm and 30 cm, between 25 cm and 35 cm, or between 30 cm
and 40 cm.
[0043] As noted above, the catheter portion 130 of the medical
device 100 may be coupled to and disposed between the first graft
portion 110 and the second graft portion 120. The catheter portion
130 of the medical device 100 may differ in composition from the
first graft portion 110 and the second graft portion 120. In some
embodiments, the catheter portion 130 has a crush force that is
greater than both the crush force of the first graft portion 110
and the crush force of the second graft portion 120. The high crush
force of the catheter portion 130 may prevent or reduce the risk of
collapse of the catheter portion 130. In some embodiments, the
catheter portion 130 has a hoop force that is greater than both the
hoop force of the first graft portion 110 and the hoop force of the
second graft portion 120. Due to the relatively high crush force
and/or hoop force of the catheter portion 130, the catheter portion
130 may be suited for positioning within a patient where strength
and/or crush resistance is warranted. For example, the catheter
portion 130 may be designed to be positioned adjacent bones or
ligaments that might cause the collapse of lumens that are formed
from weaker material. In some embodiments, the catheter portion 130
is positioned adjacent relatively sharp anatomy or in locations in
which there is significant movement. In some embodiments, the
catheter portion 130 is designed to traverse a relatively sharp
bend without kinking. The catheter portion 130 may additionally or
alternatively be designed to be positioned at a relatively exposed
location that is likely to be subjected to compression forces with
some frequency. In short, the catheter portion 130 may be
positioned within a patient at a location where strength is
warranted and/or along the portion of the flow path that is most
likely to fail or necessitate replacement.
[0044] In some embodiments, the catheter portion 130 is between 2
cm and 60 cm in length. For example, in some embodiments, the
catheter portion is between 10 cm and 50 cm in length, and/or
between 15 and 40 cm in length.
[0045] In some embodiments, the catheter portion 130 is reinforced
by metal or a metal alloy. For example, in some embodiments, the
catheter portion 130 includes a porous tube 132 that is made from
metal or metal alloy. In some embodiments, the porous tube 132 is
made from or comprises a nickel-titanium alloy, such as nitinol. In
some embodiments, the porous tube 132 is formed by winding (e.g.,
wound nitinol) or braiding (e.g., braided nitinol). In other
embodiments, the porous tube 132 is formed by laser-cutting (e.g.,
laser-cut nitinol).
[0046] In some embodiments, the porous tube 132 of the catheter
portion 130 is disposed within or between one or more polymers. For
example, in some embodiments, the porous tube is embedded within
silicone, FEP, or polyether block amide. In other embodiments, the
porous tube 132 is not embedded within a single layer. For example,
in some embodiments, the porous tube 132 is disposed between--but
not embedded withing separate polymeric layers. In some instances,
the porous tube 132 is luminal of a layer comprising silicone, FEP,
or polyether block amide. In other embodiments, the porous tube 132
is abluminal of a layer comprising silicone, FEP, or polyether
block amide.
[0047] In some embodiments, the catheter portion 130 may comprise
at least one layer that is cell impermeable meaning it is
impermeable to migration of at least certain body cells across the
layer. A cell impermeable layer may comprise silicone, FEP, or
other materials. In certain applications, a catheter portion 130
having a cell impermeable layer may be used in connection one or
more graft portions (such as first graft portion 110 and/or second
graft portion 120) which may comprise cell impermeable layers.
[0048] In some embodiments, the catheter portion 130 has a smooth
and nonporous exterior surface. The exterior surface may prevent
tissue ingrowth, thereby enabling replacement of the catheter
portion 130, such as described in greater detail below.
[0049] As noted above, connectors, such as the first connector 140
and the second connector 150, may be used to couple the catheter
portion 130 to the first graft portion 110 and the second graft
portion 120. For instance, the first connector 140 may be used to
couple the catheter portion 130 to the first graft portion 110. The
second connector 150 may be used to couple the catheter portion 130
to the second graft portion 120. Stated differently, when the
medical device 100 is fully assembled and implanted within a
patient, the first graft portion 110 may be attached to the
catheter portion 130 via a first connector 140 and the second graft
portion 120 may be attached to the catheter portion 130 via a
second connector 150.
[0050] In some embodiments, one or both of the connectors 140, 150
may include an elongate tube 142, 152 and a clamp 148, 158. In some
embodiments, the elongate tubes 142, 152 are rigid or substantially
rigid structures that are resistant to compression. In some
embodiments, the elongate tubes 142, 152 comprise a metal or a
metal alloy. In some embodiments, the elongate tubes 142, 152 are
configured such that a first portion 143, 153 of the elongate tube
142, 152 may be disposed within an inner diameter of the catheter
portion 130 while a second portion 145, 155 of the elongate tube
142, 152 may be disposed within an inner diameter of the first
graft portion 110 or the second graft portion 120. Stated
differently, each elongate tube 142, 152 may be partially disposed
within both the catheter portion 130 and either the first graft
portion 110 or the second graft portion 120.
[0051] In some embodiments, the first portions 143, 153 of the
elongate tubes 142, 152 include one or more protrusions 144, 154
that frictionally engage with the interior diameter of the catheter
portion 130. In some embodiments, any attempt to remove the
catheter portion 130 from the elongate tube 142, 152 may cause the
catheter portion 130 to "neck down" or become narrower in diameter,
thereby causing the catheter portion 130 to more tightly engage
with the elongate tube 142, 152.
[0052] In some embodiments, the second portions 145, 155 of the
elongate tubes 142, 152 include one or more protrusions 146, 156
that frictionally engage with the interior diameter of the first
graft portion 110 or the second graft portion 120.
[0053] In some embodiments, the elongate tubes 142, 152 of
connectors 140, 150 include a flange 147, 157. The flange 147, 157
may be designed to separate the catheter portion 130 from either
the first graft portion 110 or the second graft portion 120. Stated
differently, the flange 147, 157 may be disposed adjacent to and
between the catheter portion 130 and either the first graft portion
110 or the second graft portion 120.
[0054] The clamps 148, 158 may be designed to provide a compressive
force to the first graft portion 110 and/or the second graft
portion 120, thereby securing the first graft portion 110 and/or
the second graft portion 120 between the elongate tube 142, 152 and
the clamps 148, 158. In some embodiments, the clamps 148, 158 are
clam-shell clamps that include two separate portions that are
hingedly connected to one another. Stated differently, opposite
portions of the clamps 148, 158 may be rotated relative to each
other to provide a compressive force around the first graft portion
110 or the second graft portion 120. In some embodiments, the
opposite portions of clamps 148, 158 lock together as they are
rotated toward one another. For example, in some embodiments, teeth
149, 159 on the opposite portions of the clamps 148, 158 interlock
with one another as the clamps 148, 158 are secured over the first
graft portion 110 or the second graft portion 120.
[0055] In other embodiments, the connectors 140, 150 may couple the
first graft portion 110 and/or the second graft portion 120 to the
catheter portion 130 in some other way. For example, in some
embodiments, the connectors may lack clam-shell clamps.
[0056] While the embodiment depicted in FIGS. 1-6 includes a single
catheter portion 130 and two graft portions (i.e., the first graft
portion 110 and the second graft portion 120), other embodiments
may include a different number of catheter portions and/or graft
portions. For example, in some embodiments, additional connectors
may be used to couple two separate catheter portions to one
another. In some embodiments, the graft portions may be branched.
In other embodiments, only one graft portion is used. The
connectors may be used to mix and match any suitable tubular
elements to one another to create a non-natural flow path within a
patient. In some embodiments, the flow path may be formed from a
plurality of catheters. The connectors provide customizability
during a medical procedure, thereby allowing a practitioner to
connect any suitable tubular element to any other suitable tubular
element, thereby establishing a non-natural flow path.
[0057] Some embodiments relate to a kit for establishing a
non-natural flow path within a patient. The kit may include, inter
alia, the following components: a catheter 130, a first connector
140 for coupling a first graft 110 to the catheter 130, and a
second connector 150 for coupling a second graft 120 to the
catheter 130. In some embodiments, the kit further includes
instructions for implanting the catheter 130, the first graft 110,
and the second graft 120 into a patient such that the first graft
is coupled to the catheter 130 via the first connector 140 and the
second graft 120 is coupled to the catheter 130 via the second
connector 150. In some embodiments, the instructions specify that
(1) the first graft 110 is to be attached to vasculature of a
patient at a location that is above the knee of the patient and (2)
the second graft 120 is to be attached to vasculature of the
patient at a location that is below the knee of the patient. In
some embodiments, the kit further includes a cutting device (e.g.,
scissors) that is configured for shortening (e.g., cutting) the
first graft 110, the second graft 120, and/or the catheter 130.
[0058] In some circumstances, the kit may be used with any suitable
graft(s). For example, the practitioner may select a first graft
110 and/or a second graft 120 from any suitable graft, such as any
of the numerous commercially available grafts. The graft(s) may be
selected based on the characteristics desired by the practitioner.
For example, the graft(s) may be selected based on their
flexibility, tensile strength, stretchiness, size, or resistance to
kinking. In other embodiments, the kit includes one or both of the
first graft 110 and the second graft 120, wherein the first graft
110 and/or the second graft 120 are coupled to the catheter
130.
[0059] The medical device 100, the kits, and/or related components
described above may be used to establish a non-natural pathway,
such as a pathway that bypasses an occluded, partially occluded, or
damaged portion of the vasculature.
[0060] For example, in some embodiments, a practitioner may obtain
the components of the medical device 100 described above. The
practitioner may then implant the medical device 100 into a patient
such that (1) the first graft portion 110 is attached to
vasculature of the patient at a first location, (2) the second
graft portion 120 is attached to vasculature of the patient at a
second location that differs from the first location, and (3) the
catheter portion 130 is coupled to and disposed between both the
first graft portion 110 and the second graft portion 120. A medical
device 100 that has been implanted into a leg 12 of a patient 10 is
depicted in FIG. 7. The medical device 100 is implanted such that
the first graft 110 is attached to the femoral artery 14 above the
knee 16 of the patient 10, while the second graft 120 is attached
to the femoral artery 14 below the knee 16 of the patient 10,
thereby bypassing a damaged portion of the femoral artery 14. In
other embodiments, the medical device 100 is implanted at other
locations within the patient 10.
[0061] In some embodiments, the first graft portion 110 and the
second graft portion 120 are coupled to the catheter portion 130
prior to implantation. Stated differently, the assembled medical
device 100 may be inserted into the patient 10 (either
percutaneously or through an "open" surgical procedure) and then
attached to the vasculature of the patient 10 via anastomosis at
the lateral ends of the first graft portion 110 and the second
graft portion 120.
[0062] In some embodiments, one or more components of the medical
device 100 are implanted into the patient 10 before the medical
device 100 is fully assembled. For example, in some embodiments,
the catheter portion 130 is first implanted (e.g., subcutaneously)
into the patient 10. Then one or more of the first graft portion
110 and the second graft portion 120 are attached to the catheter
portion 130. In some embodiments, the first graft portion 110 may
be attached to the catheter portion 130 by partially inserting the
elongate tube 142 of the connector 140 into the catheter portion
130. The catheter portion 130 may be secured to the elongate tube
142 of the connector 140 via a friction fit. The elongate tube 142
of the connector 140 may then be partially inserted into a medial
portion of the first graft portion 110. The first graft portion 110
may be secured via placement of the clamp 148. For example,
opposite portions of a clam-shell clamp 148 may be rotated toward
one another to provide a compressive force around the first graft
portion 110. The opposite portions of the clamp 148 may lock
together, thereby securing the first graft portion 110 to the
catheter portion 130. The second graft portion 120 may be attached
to the catheter portion 130 in an analogous manner.
[0063] In some embodiments, one or both of the first graft portion
110 and the second graft portion 120 are shortened prior to (1)
attachment of the first graft portion 110 to the catheter portion
130 and/or (2) attachment of one or both of the first graft portion
110 and the second graft portion 120 to the vasculature of the
patient 10. For example, in some embodiments, a medial portion of
the first graft portion 110 is removed to shorten the first graft
portion 110 prior to coupling of the first graft portion 110 to the
catheter portion 130. In some embodiments, removal of the medial
portion may require cutting through the porous tube 114, thereby
forming exposed ends (e.g., sharp ends) at the newly formed lateral
end of the porous tube 114. The exposed ends of the porous tube 114
may be positioned adjacent the flange 147 of the elongate tube 142.
In this manner, the flange 147 may protect the patient 10 and/or
other components of the medical device 100 from the exposed ends.
The flange 147 may also protect the patient 10 from exposed ends of
the catheter portion 130. The flange 157 may operate in an
analogous manner.
[0064] In some embodiments, a lateral portion of the first graft
portion 110 is removed to shorten the first graft portion 110 prior
to attachment of the first graft portion 110 to the vasculature of
the patient 10. The removal of a lateral portion of the first graft
portion 110 may be done before or after the first graft portion 110
has been coupled to the catheter portion 130. In some embodiments,
the catheter portion 130 is shortened prior to or during
implantation into the patient 10, thereby enabling the practitioner
to select the desired length of the catheter portion 130.
[0065] In some embodiments, the medical device 100 is implanted
without using a deployment device. Stated differently, the medical
device 100 may be inserted into the patient 10 without passing
through a tubular structure. In other embodiments, the medical
device 100 (or components thereof) are implanted through a tubular
structure.
[0066] When implanted within the patient 10, the first graft
portion 110, the second graft portion 120, and the catheter portion
130 may together form the lumen 105 that extends from the first
location to the second location. In some embodiments, the surface
defining the lumen 105 includes one or more discontinuities. In
other embodiments, the lumen is defined by a smooth continuous
surface that extends across the first graft portion 110, the second
graft portion 120, and the catheter portion 130. Such a smooth and
continuous luminal surface may reduce the extent of blood
turbulence and clotting (i.e., reduce the extent of thrombus
formation).
[0067] In some embodiments, the first location and the second
location are separated from one another by a distance of more than
5 cm, 10 cm, 15 cm, 20 cm, and/or 30 cm. In some embodiments, the
first location is above a knee 16 of the patient 10, while the
second location is below the knee 16 of the patient 10. In some
embodiments, the first location is the femoral artery 14 and the
second location is the popliteal artery. Stated differently, the
medical device 100 may be used in a femoropopliteal bypass
procedure. In some embodiments, the first location is a first
femoral artery that provides blood to a first leg of the patient
and the second location is a second femoral artery that provides
blood to a second leg of the patient.
[0068] In some embodiments, both the first location and the second
location are positioned at arteries. Stated differently, the
medical device 100 may be used to establish a non-natural flow path
between a first portion of an artery and a second portion of an
artery. (The first portion of an artery and the second portion of
the artery may be different portions of the same artery or reside
on different arteries.) In some embodiments, the first location is
positioned at an artery and the second location is positioned at a
vein. Stated differently, the medical device 100 may be used to
establish a non-natural flow path between an artery and a vein. In
some embodiments, both the first location and the second location
are positioned at a vein. In other words, the medical device 100
may be used to establish a non-natural flow path between a first
portion of a vein and a second portion of a vein. (The first
portion of a vein and a second portion of a vein may be different
portions of the same vein or reside on different veins.)
[0069] In some embodiments, the patient is selected for
implantation based on a diagnosis of an occluded, partially
occluded, or damaged blood vessel. Stated differently, the medical
device 100 may be implanted into an individual to bypass an
occluded, partially occluded, or damaged blood vessel, thereby
establishing a non-natural flow path to improve the flow of blood
to a region (e.g., a peripheral region) of the patient's body.
[0070] In some embodiments, the catheter portion 130 of the medical
device 100 may be removed from the patient 10 without removing the
first graft portion 110 and/or the second graft portion 120.
[0071] For example, in some embodiments, the practitioner may make
an incision in a patient 10 to provide access to at least a portion
of the medical device 100 which had been previously implanted into
the patient 10. In some embodiments, the catheter portion 130 of
the medical device 100 may be made from material that is resistant
to tissue ingrowth, while one or both of the first graft portion
110 and the second graft portion 120 permit tissue ingrowth. Stated
differently the tissue of the patient 10 may be intimately
connected with the first graft portion 110 and the second graft
portion 120, but less intimately associated with the catheter
portion 130. In some instances, at the time of the removal
procedure, the medical device 100 had been implanted into the
patient 10 for at least one week, one month, and/or one year. Once
the practitioner has established access with at least a portion of
the medical device 100, the catheter portion 130 may then be
uncoupled from the first graft portion 110 and the second graft
portion 120. For example, in some embodiments, the connectors 140,
150 may be unlocked and/or released, thereby allowing the first
graft portion 110 and the second graft portion 120 to be uncoupled
from the elongate tubes 142, 152 of the connectors 140, 150. Once
uncoupled from the first graft portion 110 and the second graft
portion 120, the catheter portion 130 may then be removed from the
patient 10. A second catheter portion (not shown) may then be
coupled to the first graft portion 110 and the second graft portion
120 while the first graft portion 110 and the second graft portion
120 remain attached to vasculature of the patient 10. Such
attachment may be accomplished via any suitable connector, such as
the connectors 140, 150 described herein. In this manner, the
catheter portion 130 of the medical device 100 may be replaced
without removing the first graft portion 110 and the second graft
portion 120 from the patient 10.
[0072] FIG. 8 depicts an embodiment of a medical device 200 that
resembles the medical device 100 described above in certain
respects. Accordingly, like features are designated with like
reference numerals, with the leading digits incremented to "2." For
example, the embodiment depicted in FIG. 8 includes a catheter
portion 230 that may, in some respects, resemble the catheter
portion 130 of FIGS. 1-7. Relevant disclosure set forth above
regarding similarly identified features thus may not be repeated
hereafter. Moreover, specific features of the medical device 100
and related components shown in FIGS. 1-7 may not be shown or
identified by a reference numeral in the drawings or specifically
discussed in the written description that follows. However, such
features may clearly be the same, or substantially the same, as
features depicted in other embodiments and/or described with
respect to such embodiments. Accordingly, the relevant descriptions
of such features apply equally to the features of the medical
device 200 and related components depicted in FIG. 8. Any suitable
combination of the features, and variations of the same, described
with respect to the medical device 100 and related components
illustrated in FIGS. 1-7 can be employed with the medical device
200 and related components of FIG. 8, and vice versa. This pattern
of disclosure applies equally to further embodiments depicted in
subsequent figures and described hereafter, wherein the leading
digits may be further incremented.
[0073] FIG. 8 provides a perspective view of a portion of a medical
device 200. The view provided in FIG. 8 shows the attachment of a
first graft portion 210 to the catheter portion 230. The medical
device 200 is identical to the medical device 100 except that the
first graft portion 210 further includes beading 219 disposed
around an outer surface (e.g., a circumference) of the first graft
portion 210 and/or the second graft portion (not shown). In some
embodiments, the beading 219 is helical in shape. In some
embodiments, the helical beading 219 comprises or consists of PTFE.
The beading 219 may reduce the propensity of the first graft
portion 210 for kinking. In other words, the beading 219 may lessen
the likelihood that the first graft portion 210 will become
kinked.
[0074] FIG. 9 depicts another embodiment of a medical device 300.
The medical device 300 is generally analogous to the medical
devices 100, 200 discussed above, except that the medical device
300 includes one or more tapers 311, 321. For example, in some
embodiments, the first graft portion 310 includes a taper 311 such
that a lateral portion of the first graft portion 310 is narrower
(e.g., has a smaller circumference) than a medial portion of the
first graft portion 310. The taper 311 of the first graft portion
310 may be designed to facilitate anastomosis to vasculature at a
particular location within a patient. Stated differently, the taper
311 may be selected such that the diameter of a lateral end of the
first graft portion 310 closely matches the diameter of vasculature
of the patient to which the first graft portion 310 is to be
attached. In some embodiments, the first graft portion 310 may
taper such that the inner diameter of the first graft portion 310
narrows from the medial end to the lateral end by between 1.5 mm
and 5 mm, such as between 2 mm and 4 mm. For example, the first
graft portion 110 may taper from an inner diameter of between 6.5
mm and 9 mm at a medial end to an inner diameter at a lateral end
that is between 2 and 4 mm smaller. In embodiments in which the
second graft portion 320 includes a taper 321, the taper 321 may
have any of the features or characteristics discussed above in
connection with the taper 311. In other embodiments, one of the
first graft portion 310 and the second graft portion 320 includes a
taper, but the other does not.
[0075] FIGS. 10-11A depict another embodiment of a medical device
400. The medical device 400 is generally analogous to the medical
devices 100, 200, 300 discussed above. However, the medical device
400 differs from the medical devices 100, 200, 300 in that the
medical device 400 lacks connectors.
[0076] In the embodiment depicted in FIGS. 10-11A, the medical
device 400 includes a first graft portion 410, a second graft
portion 420, and a catheter portion 430. The first graft portion
410 and the second graft portion 420 are formed from a single
tubular structure 401. In other words, in addition to forming the
first graft portion 410 and the second graft portion 420, the
single tubular structure 401 extends through and is a component of
the catheter portion 430. The remaining component of the catheter
portion 430--tubular structure 434--may be analogous or identical
in composition and structure to the catheter portions (e.g.,
catheter portions 130, 230) discussed above.
[0077] The inner surface of a lumen 405 formed by the first graft
portion 410, the second graft portion 420, and the catheter portion
430 has a smooth continuous surface that extends across the first
graft portion 410, the second graft portion 420, and the catheter
portion 430. Such a smooth and continuous luminal surface may
reduce the extent of blood turbulence and clotting.
[0078] FIG. 11B provides a cross-sectional side view of a medical
device 400' according to another embodiment. The medical device
400' is generally analogous to the medical device 400 discussed
above in connection with FIGS. 10 and 11A. The medical device 400'
includes a first graft portion 410', a second graft portion 420',
and a catheter portion 430'. In the depicted embodiment, the first
graft portion includes 410' includes a portion of a tubular
structure 401' that extends through the medical device 400', a
portion of a porous PTFE layer 407', and an intervening layer 415'.
The second graft portion 420' may likewise include a portion of the
tubular structure 401', a portion of a porous PTFE layer 407', and
an intervening layer 425'. The catheter portion 430' includes a
portion of the tubular structure 401', the tubular structure 434,
and a portion of the porous PTFE layer 423'. In some embodiments,
the tubular structure 401' is analogous in composition and/or
structure to the first graft portions (e.g., first graft portions
110 and 120) discussed above in other embodiments.
[0079] In some embodiments, the porous PTFE layer 407' and/or the
tubular structure 401' is formed from expanded PTFE. In other
embodiments, the porous PTFE layer 407' and/or the tubular
structure 401' is formed from fibrous PTFE, such as electrospun or
rotational spun PTFE. The porous PTFE layer(s) 407' and/or 401' can
reduce thrombus formation and/or promote tissue incorporation
(while eliciting little or no inflammation). (In some embodiments,
the porous PTFE layer 407' and/or the tubular structure 401' may be
replaced with a silicone layer. The silicone may be applied via a
spray or could be formed as an extruded tube. The silicone layer
may be configured for contact with blood.)
[0080] In some embodiments, each of the intervening layers 415' and
425' comprises or consists of fluorinated ethylene propylene (FEP).
In other embodiments, no intervening layers are used. For example,
in some embodiments, the porous PTFE layer 407' may be thicker
adjacent the lateral ends of the medical device 400' than in a
medial region of the medical device 400'. In such embodiments, a
single porous PTFE layer may occupy the regions identified in FIG.
11B with reference numbers 407', 415', and 425'.
[0081] In some embodiments, the medical device 400' may have a
constant inner diameter (e.g., a diameter defined by the tubular
structure 401'. In other or further embodiments, the medical device
400' may have a constant outer diameter (e.g., a diameter defined
by the porous PTFE layer 407'. The constant diameter(s) of the
inner and/or outer layers may improve biocompatibility and reduce
thrombus formation of the medical device 400', facilitate placement
of the medical device 400', and/or decrease fluid turbulence
through the lumen 405' of the medical device 400'.
[0082] FIGS. 12-14 provide distinct configurations of an
alternative graft portion 510 for a medical device. The graft
portion 510 may be used in a manner analogous to the first graft
portions and second graft portions described above. In the depicted
embodiment, the graft portion 510 includes a porous tube 514 that
extends along substantially the entire length of the graft portion
510. The porous tube 514 may increase the crush force and/or hoop
force of the graft portion 510 relative to embodiments that lacks
the porous tube 514.
[0083] The graft portion 510 may additionally or alternatively
include a collar 570 that is disposed around a periphery of the
remainder of the graft portion 510. In some embodiments, the collar
570 is configured to transition between a compact state (FIG. 12)
in which the collar 570 adopts a low-profile configuration to a
deployed state (FIGS. 13 and 14) in which the collar 570 extends
outward from the exterior surface of the remainder of the graft
portion 510. To attach the graft portion 510 to the vasculature 18
of the patient, the lateral end of the graft portion 510 may
initially be inserted into the vasculature 18 (e.g., an artery or
vein) of the patient while the collar 570 is in a compact state
(e.g., as shown in FIG. 12). Once the graft portion 510 has been
partially inserted into the vasculature 18 of the patient, the
collar 570 may transition to the deployed state as shown in FIG.
13.
[0084] In some embodiments, the porous tube 514 of the graft
portion 510 is expandable such that the graft portion 510 is
configured to transition from a relatively compact state within a
deployment device to an expanded state when deployed through the
deployment device. In some instances, the collar 570 may be
deployed before the entire graft portion 510 is deployed to
facilitate positioning of the graft portion 510. For example, the
expanded collar 570 may be brought into contact with a wall of the
vasculature 18 of the patient before the entire graft portion 510
is expanded and is thus more easily displaceable. The collar 570
may be any suitable shape. For example, in the depicted embodiment,
the collar 570 is a relatively thin, ring-shaped sheet of
material.
[0085] In some embodiments, the collar 570, when unconstrained, is
angled relative to the remainder of the graft portion 510. For
example, the collar 570 may form an acute angle (.theta.) with the
remainder of the graft portion 510. In some embodiments, the acute
angle .theta. is between 15.degree. and 75.degree., between
30.degree. and 60.degree., and/or between 35.degree. and
55.degree.. The angled relationship between the collar 570 and the
remainder of the graft portion 510 may facilitate positioning of
the collar 570 to function as a seal. For example, as shown in FIG.
14, the deployed collar 570 may function as a seal, thereby
preventing or reducing the leakage of blood from the opening in the
vasculature 18 into which the graft portion 510 has been inserted.
The collar 570 may also prevent or reduce the risk of withdrawal of
the graft portion 510 from the vasculature 18. Stated differently,
the collar 570 may serve as a stop that prevents withdrawal of the
graft portion 510 from the vasculature 18. In other embodiments,
one or more graft portions of the medical device is attached to
vasculature via other methods (e.g., traditional anastomosis). In
some embodiments, one or more graft portions are attached via
sutures. In some embodiments, one or more graft portions are
attached via suture-less fasteners, such as staples.
[0086] Any methods disclosed herein include one or more steps or
actions for performing the described method. The method steps
and/or actions may be interchanged with one another. In other
words, unless a specific order of steps or actions is required for
proper operation of the embodiment, the order and/or use of
specific steps and/or actions may be modified. Moreover,
sub-routines or only a portion of a method described herein may be
a separate method within the scope of this disclosure. Stated
otherwise, some methods may include only a portion of the steps
described in a more detailed method.
[0087] Reference throughout this specification to "an embodiment"
or "the embodiment" means that a particular feature, structure, or
characteristic described in connection with that embodiment is
included in at least one embodiment. Thus, the quoted phrases, or
variations thereof, as recited throughout this specification are
not necessarily all referring to the same embodiment.
[0088] Similarly, it should be appreciated by one of skill in the
art with the benefit of this disclosure that in the above
description of embodiments, various features are sometimes grouped
together in a single embodiment, figure, or description thereof for
the purpose of streamlining the disclosure. This method of
disclosure, however, is not to be interpreted as reflecting an
intention that any claim requires more features than those
expressly recited in that claim. Rather, as the following claims
reflect, inventive aspects lie in a combination of fewer than all
features of any single foregoing disclosed embodiment. Thus, the
claims following this Detailed Description are hereby expressly
incorporated into this Detailed Description, with each claim
standing on its own as a separate embodiment. This disclosure
includes all permutations of the independent claims with their
dependent claims.
[0089] Recitation in the claims of the term "first" with respect to
a feature or element does not necessarily imply the existence of a
second or additional such feature or element. It will be apparent
to those having skill in the art that changes may be made to the
details of the above-described embodiments without departing from
the underlying principles of the present disclosure.
* * * * *